Pressure swing adsorption nitrogen production

At adsorption equilibrium, when any adsorbent is used to adsorb the same gas, the higher the gas pressure, the greater the amount of gas that can be adsorbed by the adsorbent. Conversely, the lower the pressure, the smaller the adsorption amount. As shown in the figure below: As mentioned above, when air pressure increases, carbon molecular sieves will adsorb large amounts of oxygen, carbon dioxide, and moisture. When the pressure is reduced to atmospheric pressure, the adsorption capacity of carbon molecular sieves for oxygen, carbon dioxide, and moisture is very low. The pressure swing adsorption unit mainly consists of two adsorption towers, A and B, equipped with carbon molecular sieves, along with a control system. When compressed air (with a pressure of generally 0.8 MPa) passes through Tower A from bottom to top, oxygen, carbon dioxide, and moisture are adsorbed by the carbon molecular sieve, while nitrogen passes through and flows out from the top of the tower. When the molecular sieve in Tower A becomes saturated with adsorbates, the process shifts to Tower B for the aforementioned adsorption, while simultaneously regenerating the molecular sieve in Tower A. Regeneration refers to the process of releasing the gas inside the adsorption tower into the atmosphere, thereby rapidly reducing the pressure to atmospheric levels and allowing the oxygen, carbon dioxide, and moisture adsorbed by the molecular sieve to be released from it.